Tuesday, December 22, 2015

Admitting ICU diagnosis is a poor predictor of infection

We studied a cohort
of critically ill patients admitted with clinically suspected sepsis
to two tertiary ICUs in the Netherlands between January 2011 and
December 2013. The likelihood of infection was categorized as none,
possible, probable or definite by post-hoc assessment. We used
multivariable competing risks survival analyses to determine the
association of the plausibility of infection with mortality.

Results

Among 2579 patients
treated for sepsis, 13% had a post-hoc infection likelihood of
“none”, and an additional 30% of only “possible”. These
percentages were largely similar for different suspected sites of
infection. In crude analyses, the likelihood of infection was
associated with increased length of stay and complications. In
multivariable analysis, patients with an unlikely infection had a
higher mortality rate compared to patients with a definite infection
(subdistribution hazard ratio 1.23; 95% confidence interval
1.03-1.49).

Conclusions

This study is the
first prospective analysis to show that the clinical diagnosis of
sepsis upon ICU admission corresponds poorly with the presence of
infection on post-hoc assessment. A higher likelihood of infection
does not adversely influence outcome in this population.

There are some
important lessons from this study. Though we often have to
aggressively give antibiotics “just in case” in severely ill
patients, who often have undifferentiated presentations, many of
these will turn out not to be infected. This speaks for the
importance of diligent efforts to de-escalate. In order to
facilitate rapid initiation of antibiotics, remember that sepsis is
defined clinically. That is, the definition requires only that
infection be suspected, not established. It is a clinical syndrome
more than it is a diagnosis (in much the same way ARDS is a syndrome
rather than a specific diagnosis). The findings in this paper
provide one more illustration of how unrealistic it is to expect
clinicians to assign a specific diagnosis on the front end even
though that is what the coders would like us to do.